Nonclustered Indexes

  • Thanks for the question!

  • ops


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  • GilaMonster (12/7/2010)


    Another phrasing problem with the question - the maximum size of an index is not 900 bytes. The maximum size of the key columns is 900 bytes. The index row can technically be up to 8000 bytes.

    Although what you say is correct, your wording also seems misleading.

    The actual limitation is listed in the reference material as:

    Index key columns, excluding nonkeys, must follow the existing index size restrictions of 16 key columns maximum, and a total index key size of 900 bytes.

    😎

  • SanDroid (12/7/2010)


    Although what you say is correct, your wording also seems misleading.

    Why?

    GilaMonster (12/7/2010)


    Another phrasing problem with the question - the maximum size of an index is not 900 bytes. The maximum size of the key columns is 900 bytes. The index row can technically be up to 8000 bytes.

    Index key columns, excluding nonkeys, must follow the existing index size restrictions of 16 key columns maximum, and a total index key size of 900 bytes.

    😎

    What's different about what you said and what I said?

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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  • GilaMonster (12/7/2010)


    SanDroid (12/7/2010)


    Although what you say is correct, your wording also seems misleading.

    Why?

    GilaMonster (12/7/2010)


    Another phrasing problem with the question - the maximum size of an index is not 900 bytes. The maximum size of the key columns is 900 bytes. The index row can technically be up to 8000 bytes.

    Index key columns, excluding nonkeys, must follow the existing index size restrictions of 16 key columns maximum, and a total index key size of 900 bytes.

    😎

    What's different about what you said and what I said?

    I think he is trying to say the difference between "total index key size of 900 bytes" and "maximum size of the key columns is 900 bytes". I don't know but can the "total key size" ever be larger than the "size of the key columns"? (Like in the case of a uniquefier automatically added to a clustered index?)

  • GilaMonster (12/7/2010)


    SanDroid (12/7/2010)


    Although what you say is correct, your wording also seems misleading.

    Why?

    He left out the word "key" in his question, you left the word "index" out of your rebuttle.

    😀

  • Edit: Never mind.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • da-zero (12/7/2010)


    Furthermore, even if you did take in account included columns, no answer could have been correct.

    Considering that you can have up to 1023 (max columns in a table -1) non-key included columns in an index that would be a very differant answer.

    Has anyone experianced any limitations when working with non-key columns included in an Index?

  • Thanks for the question

    Jason...AKA CirqueDeSQLeil
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